Simultaneous Optimization of a Wheeled Mobile Robot Structure and a Control Parameter

A wheeled mobile mechanism with a passive and/or active linkage mechanism for traveling in the outdoor environment is developed and evaluated. In our previous research, we developed a wheeled mobile robot which has six wheels and a passive linkage mechanism, and its maneuverability was experimentally verified. The ability to climb over a 0.20 [m] high bump, which is twice height of the wheel diameter of 0.10 [m], was achieved, and the mobile robot can climb up continuous steps of 0.15 [m] high. In this research, we optimized the mobile robot linkage mechanisms and a controller parameter by evolutionary algorithm and dynamics engine in numerical simulations. The evolutionary algorithm employed in this research is Genetic Algorithm, and Open Dynamics Engine is used for dynamics calculation. To optimize the linkage mechanism and a controller parameter, we investigated outdoor environment for the mobile robot, for example obstacles, steps, and stairs. And, we selected typical three kinds of outdoor environments, 0.20 [m] high bump, right angle stairs of 0.15 [m] high, and angled stairs of 0.15 [m] high. In the numerical simulations, though the mobile robot using parameters which express our existing robot could climb up/down the 0.20 [m] high bump, but it could not achieve climbing up/down the two kinds of stairs. On the other hand, the optimized parameter mobile robot could climb up/down the three kinds of typical environments

ホエイペプチドの生理機能に関する研究

学位の種別:論文博士University of Tokyo(東京大学

Microbial biomass in relation to primary succession on arctic deglaciated moraines

Microbial biomass in arctic soil was examined in relation to a primary succession on arctic deglaciated moraines in Ny-Alesund, Svalbard (79°N, 12°E). Soil samples at four study sites representing different successional stages were collected at every 1cm depth from the soil surface to 3cm depth in early August 1995. Microbial biomass was measured with a substrate-induced respiration procedure. The microbial biomass was highest at the soil surface (0-1cm depth) in all successional stages, and decreased to a negligible amount at 3cm depth. Mean microbial biomass in 0-2cm layer increased from 0.06mgCg^ soil d. w. in the youngest site to 1.03mgC g^ soil d. w. in the oldest site, which is comparable to ecosystems in warmer regions. Throughout all successional stages, there was positive high correlation between soil carbon or nitrogen content and microbial biomass

Soil respiration in a high arctic glacier foreland in Ny-Alesund, Svalbard

Soil respiration rates were measured in a successional glacier foreland in Ny-_lesund, Svalbard, and the amount of CO2 efflux during the plant-growing season was estimated using a simple regression model. Three study sites (Site 1, Site 2 and Site 3) were set up along with the primary succession in the deglaciated area of East Br_gger glacier in Ny-_lesund, Svalbard, Norway (79‹N 12‹E). Another study site, Site RB, was set up on a riverbed in the Bay River between Site 2 and Site 3. Soil respiration (SR), air temperature at 10 cm height (AT), soil surface temperature (SST) and soil temperature at 1 cm depth (ST) were measured at the four study sites with an open-airflow system using an infra-red gas analyzer from July to August, 1995. The mean soil respiration rate varied among the four sites: 6.2, 44, 63 and 3.7 mg CO2 m-2 h-1 at Site 1, Site 2, Site 3 and Site RB, respectively. These differences in the soil respiration rate among the four sites corresponded with the soil organic amount, microbial biomass, and root biomass. The soil respiration rate showed the best correlation with AT at Site 1, Site 2 and Site RB, and with ST at Site 3. The cumulative amount of CO2 efflux calculated using correlation equations obtained from the above relationships between SR and AT or ST was 5.8, 46, 69 and 3.3 g CO2 m-2 at Site 1, Site 2, Site 3 and Site RB, respectively, for two months (from July to August, 1995). These values were extremely low compared to those of warmer ecosystems, such as low-arctic tundra, temperate mixed forests, and tropical moist forests

A Kampo Medicine, Boi-ogi-to, Inhibits Obesity in Ovariectomized Rats

In women facing menopause, end of menstrual activity is accompanied by lower levels of estrogen and gradual weight gain. Postmenopausal weight gain sounds an alarm for women's health and may lead to hyperlipidemia, a lipid increase and glucose intolerance. These phenomena are connected to lifestyle-related diseases such as hypertension, type II diabetes mellitus, arteriosclerosis and metabolic syndrome, making it essential to prevent weight gain in women. A Kampo medicine, Boi-ogi-to, is traditionally used to treat obese conditions, but the mechanism has not yet been investigated. In this experiment, we tested the antiobesity properties of Boi-ogi-to in ovariectomized rats by measuring changes of serum cytokine levels and adipocytokines in fat cells. After treatment with this extract for 6 weeks (20-week-old rats), we found that there was a significant weight decrease in rats treated with Boi-ogi-to as compared with that in the control group. Serum tumor necrosis factor (TNF)-α levels increased significantly in a dose-dependent manner. Gene expression of adipose tissue in uterus also dose dependently showed a significant increase of TNF-α levels, suggesting that secretion of TNF-α by fat cells might play a role in the ability of Boi-ogi-to to inhibit weight gain. While peroxisome proliferators-activated receptor-γ and adiponectin levels did not show a significant difference as compared with those in the control, levels of mRNA expression showed a tendency to increase dose dependently. Resistin did not show any significant change. These results suggest that Boi-ogi-to might be useful for the prevention of obesity that occurs in women with reduction of estrogen

Interleukin(IL)-36α and IL-36γ Induce Proinflammatory Mediators from Human Colonic Subepithelial Myofibroblasts

Background: Interleukin (IL)-36 cytokines are recently reported member of the IL-1 cytokine family. However, there is little information regarding the association between IL-36 cytokines and gut inflammation. In the present study, we investigated the biological activity of IL-36α and IL-36γ using human colonic subepithelial myofibroblasts (SEMFs). Methods: The mRNA expression and the protein expression of target molecules in SEMFs were evaluated using real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. The intracellular signaling of IL-36 cytokines was analyzed using Western blot analysis and small interfering RNAs (siRNAs) specific for MyD88 adaptor proteins (MyD88 and IRAK1) and NF-κB p65. Results: IL-36α and IL-36γ significantly enhanced the secretion of IL-6 and CXC chemokines (CXCL1, CXCL2, and CXCL8) by SEMFs. The combination of IL-36α/γ and IL-17A or of IL-36α/γ and tumor necrosis factor (TNF)-α showed a synergistic effect on the induction of IL-6 and CXC chemokines. The mRNA expression of proinflammatory mediators induced by IL-36α and/or IL-36γ was significantly suppressed by transfection of siRNA for MyD88 or IRAK1. Both inhibitors of mitogen activated protein kinases (MAPKs) and siRNAs specific for NF-κBp65 significantly reduced the expression of IL-6 and CXC chemokines induced by IL-36α and/or IL-36γ. Conclusion: These results suggest that IL-36α and IL-36γ contribute to gut inflammation through the induction of proinflammatory mediators

Magnetic interaction in superparamagnetic Co-Pt nanoparticles synthesized in protein crystal

We synthesized Co-Pt nanoparticles in a crystal composed of proteins with a cage structure (i.e., Pyrococcus furiosus virus-like particle (PfV)) and investigated their magnetic interactions. When the soaking concentrations of metal, Co, and Pt ions in the PfV crystal were below 5.5 mM, isolated Co-Pt nanoparticles were formed. The size of the primary particles was 2-3 nm, which was smaller than the inner core size of the cage structure. When the soaking concentrations increased above 11 mM, the Co-Pt nanoparticles formed aggregates exceeding 30 nm in size. The synthesized nanoparticles showed superparamagnetic behavior at 300 K, independent of the soaking concentration. The temperature dependence of the AC magnetic susceptibility and remanent magnetization curve verified the occurrence of magnetic interactions between the Co-Pt nanoparticles. These measurements revealed that the dipolar-dipolar interaction was significant in the closely packed isolated nanoparticles, whereas it was weaker in the aggregated Co-Pt nanoparticles, probably due to the increased distance between the particles.Tagata K., Kanda D., Kobayashi N., et al. Magnetic interaction in superparamagnetic Co-Pt nanoparticles synthesized in protein crystal. IEEE Transactions on Magnetics , (2023); https://doi.org/10.1109/TMAG.2023.3290367